


Accidental Child

by Akiko_Natsuko



Series: Gratsu [12]
Category: Fairy Tail
Genre: Age Regression/De-Aging, Established Relationship, Friendship/Love, M/M, Magic Gone Wrong, Protectiveness, Trust, accidental magic
Language: English
Status: Completed
Published: 2018-10-01
Updated: 2018-10-01
Packaged: 2019-08-17 06:41:27
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,370
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16511240
Author URL: https://archiveofourown.org/users/Akiko_Natsuko/pseuds/Akiko_Natsuko
Summary: Gray finds himself confronting parenthood when Natsu finds himself the victim of a magical accident, and worse he just can't say no to those pleading eyes.





	Accidental Child

   Gray wanted to bang his head against the wall in the hopes that it would change the sight in front of him, he’d already tried closing his eyes and reopening them and pinching himself, but so far nothing had changed the image in front of him. Instead of giving into the temptation, he settled for fixing a sheepish looking Levy and Freed with a dark glare. They both winced at the anger and worry they could see lurking beneath the shock, and they struggled to keep their eyes away from the source of his ire.

“How did this happen?” Gray demanded as he gestured at the small, pink-haired child sitting on the ground between them in a pile of clothes that were now way too big for him. The boy’s head was swivelling between them all with a confused expression on his face although his gaze lingered on the Ice mage.

“Erm…” Levy whispered, realising for the first time just how terrifying Gray could be especially when he seemed to be channelling Erza, a chill seeping into the air around them as his magic reacted to his ire, and she trailed off as she glanced helplessly at Freed.

“We were experimenting with a new spell.” Freed muttered glancing briefly at the child before a low growl from Gray had him hastily raising his head, his voice terse as he continued with his explanation. “Levy found an old spell that combines both of our magic, one that’s supposed to reduce the size of an inanimate object and we wanted to see if it works.” He had leapt at the chance to do some research for once, especially as the Raijinshuu were on a break at the moment as Bickslow had been injured on their last job, now though he wished that he had just taken a simple job somewhere instead as he squirmed beneath Gray’s piercing gaze.

“And how did that result in this?” Gray asked tersely, the logical part of him acknowledging that this was simply an accident. Unfortunately for all of them, the logical part of him tended to take a backseat whenever something happened to Natsu, and he counted having his mate being turned into a small child as one of those situations.

“Natsu startled us,” Freed replied with a sigh, pinching the top of his nose as he glanced across at the runes written on the floor and frowning as he explained. “He burst in here, right in the middle of the spell, and stopped smack bang in the middle of the runic circle and the spell targeted him instead.” Gray sighed slightly at this, knowing that was something his idiotic mate would do, and he felt his anger at the pair easing slightly as he realised that there really hadn’t been anything they could’ve done to prevent this. He would have to have strong words with Natsu about rushing into things once the Dragon-slayer was back to his proper age, speaking of which…

“Can you reverse it?”

“I…” Levy began, wringing her hands together as she glanced across at Natsu before sighing and admitting quietly. “Maybe.” In all honesty, she wasn’t sure why the spell had worked on a human being in the first place, and she had no idea where to even begin to start undoing it, but she wasn’t about to admit that part aloud when Gray was still glowering at them.

“Maybe?! Maybe!” Gray knew he was shouting and that it wasn’t going to help anything, but he couldn’t stop himself, panic welling up in him at the thought of Natsu winding up stuck like this for good. “Damn it! I want my m…” He was cut off when he felt something tugging at his trouser leg, and he glanced down blinking in shock as he realised that Natsu had  used their direction to move across to his side whilst he was distracted and was now peering up at him with wide, olive eyes. “Natsu?”

“Am I in trouble?” Natsu asked, and there was a hint of fear in his eyes, and Gray immediately felt all his irritation draining away. Moving slowly so that he didn’t startle the Dragon-slayer he carefully reached down and scooped Natsu up into his arms, startled by how small and light Natsu was and unbelievably relieved when the Dragon-slayer cuddled up against him - unsure of what he would have done if Natsu had feared him.

“No,” Gray reassured him softly, before turning to glower at Levy and Freed who were watching their interaction with wide eyes. “But they are…” Natsu twisted in his arms so that he could peer at them as well, tilting his head curiously and with more than a hint of confusion in his expression, clearly not understanding why they were getting told off, and Gray had no intention of explaining. “Just find a way to fix this,” he hissed at them, and they could hear the ‘or else’ that he didn’t voice.

“What are you going to do?” Levy asked cautiously when the Ice mage turned and began to head for the door, and Gray paused to glance back at her, seeing the honest concern in her face which made him bite back the irritated response he had initially been going to give.

“I’m going to find him some clothes that fit,” he replied tilting his head down to Natsu, and her eyes widened when she realised that he was wearing nothing more than his vest and scarf, both of

which were practically drowning him. At that moment Natsu’s stomach rumbled loudly, and for the first time since he’d discovered his de-aged mate Gray felt his lips twitching up in a smile, trust the Dragon-slayer not to lose his appetite even in this situation, and his voice was louder as he added. “And some food and let the others know what’s happened.”

“We’ll come and find you when we have something,” Freed promised relieved to see the smile, although he winced as he imagined just how the rest of the guild would react and he could see Levy squirming out of the corner of his eye.

“Thank you,” Gray muttered with a nod, before lifting a hand in farewell before heading out of the room with Natsu.

****

  The rest of the guild had been shocked into silence when Gray had appeared in their midst, with a tiny version of their Fire Dragon-slayer clutched protectively in his arms, and it was only his dark glare that had stopped them all from swamping the pair. The Ice mage had hastily taken advantage of the silence to explain what was happening, frequently interrupted by Natsu who didn’t understand what was happening and the guild found themselves marvelling yet again at how tender the Ice mage could be with him. Once he was finished Macao disappeared to try and find some of Romeo’s old clothes that might fit Natsu, whilst Makarov had headed off to help Levy and Freed work out what had gone wrong whilst Gray had retreated to a corner with Natsu where he was joined by the rest of their team-mates.

“Only Natsu,” Lucy muttered as she stared curiously at the tiny child with interest, smiling at how Gray was fussing around him as he got him settled and sharing an amused glance with Erza. Natsu didn’t seem to know what to make of them at the moment and kept shooting them slightly wary glances from where he was partially hidden next to Gray’s side, Happy. However, he had taken to in an instance, and the Exceed was currently sat right next to him.

“He’s lucky that spell didn’t do more damage,” Erza muttered with a sigh, but she couldn’t hold onto her irritation as she watched Natsu starting around the hall with wide eyes. She remembered how mesmerised he had been by the guild when he’d first arrived, and this version seemed even younger than he had been then.

   Mira appeared a few moments later with a large bowl of soup and bread for Natsu, explaining that they should stick to simple foods as they didn’t know what the spell had done…or if they would be able to transform him back that day. Natsu didn’t seem to mind though, eagerly digging in as soon as Gray told him he could contribute much to the Ice mage’s consternation.

“Where’s Igneel?” Natsu asked suddenly a short while later as he glanced up from the nearly empty bowl of soup, blinking as he gazed around as though expecting the huge Dragon to appear at any moment and Gray froze, paling as the question registered…At least that answers the question of what he remembers, but why did that have to be the first thing he asked?

“He had to go and take care of something, so he asked us to look after you,” Lucy interjected smoothly when she caught the overwhelmed expression on the Ice mage’s face, watching Erza nudge him sharply in the side to break him out of his thoughts before Natsu worked out that something was wrong.

“Oh,” Natsu pouted slightly, and both girls had to fight tooth and nail against the urge to squeal at the sight. Erza couldn’t believe how cute she was finding the Dragon-slayer…fairly sure that ‘cute’ had never really been a word that she had associated with him back when they were children. After a moment though he seemed to shake it off, resuming eating with a happy smile and Gray nearly melted into a puddle of relief as he mouthed a silent thank you to Lucy who merely nodded and smiled.

   It didn’t take long for Natsu to finish his food, and just as he pushed the bowl away, Macao reappeared with a t-shirt and shorts for him to wear and whilst they were slightly too big, they were at least better than his own clothes. Gray had swiftly helped him dress, ignoring the quiet awws that he could hear coming from the girls…the only trouble coming when he had to remove Natsu’s scarf to get the t-shirt on, as Natsu had nearly burst into tears when he thought it was being taken away and it had taken several minutes of frantic reassurances to convince him that wasn’t the case, and he was still sniffling afterwards his tiny arms wrapped protectively around it. Gray wanted to kick himself for putting that kind of expression on Natsu’s face, and he glanced helplessly at the others for inspiration on how to cheer the child up.

   Seeing this Happy leaned over and whispered something in Natsu’s ear, grinning at a suddenly apprehensive Gray when the Dragon-slayer’s face lit up, and the Ice mage swallowed when Natsu turned to look at him with large eyes…How the hell am I going to resist that look? I can’t resist it now when he’s practically an adult…let alone when he’s so little… Gray was screaming in his head, already knowing that he was going to give in to whatever was going to ask, and with a slightly resigned look, he nodded to Natsu to speak.

“Can we go play outside?” Natsu was practically bouncing in his seat now, excitement and hope written on his face.

“Er…” Gray hesitated for a brief moment, every possible thing that could go wrong immediately flashing through his mind as he realised just how vulnerable Natsu was in this state…not that he had any intention of letting anything happen to the Dragon-slayer.

“Please,” Natsu pleaded as he caught the hesitation, his eyes filling slightly at the thought of being told no and he glanced around frantically before his face lit up as his eyes landed on the Exceed that was watching the conversation with amusement and exclaiming loudly. “Happy wants to!” Happy sweat-dropped at the argument, but he couldn’t bring himself to argue back and settled for a sheepish.

“Aye Sir!”

“Alright but not for too long,” Gray agreed with a sigh, resolutely ignoring the knowing looks that the girls were giving him as he got to his feet so that Natsu could slide get out as well. The Dragon-slayer was cheering happily, a broad grin on his face that melted away the last of the Icemage’s resistance and Gray smiled as he watched Natsu dashing towards the door with Happy close on his heels. “We’ll be back in a bit,” he muttered to Lucy and Erza who waved him off with broad grins. However, he had barely begun to turn to go after Natsu when he heard the Dragon-slayer calling out to him in panic and cursing himself for getting distracted even for a moment the Ice mage whirled around, only to blink as he realised that Natsu had just managed to run headfirst into Laxus in his hurry to go out and play.

   Although taking in the hulking form of the Lightning mage as it towered over Natsu, he couldn’t blame Natsu for being scared, and he quickly made his way across to them, trying not to laugh at the completely stunned expression on Laxus’s face as he studied the child in front of him. The moment that he reached them Natsu dove behind him, gripping the back of his trousers as he peered nervously up at Laxus and Gray could feel him trembling slightly.

“Easy Natsu,” Gray soothed as he reached down to lay a hand on Natsu’s head, waiting until olive eyes rose to meet his gaze before continuing. “This is Laxus one of my friends. Try and look a bit less threatening!” He hissed the last bit at Laxus, narrowing his eyes at the taller man who was still gawking at Natsu, his brow pulled down into a confused scowl which made him look even scarier than usual.

“What the hell happened?” Laxus demanded, ignoring the irritated glare he received for his language and Gray sighed before explaining yet again what had happened.

“Natsu walked into the middle of one of Levy and Freed’s experiments,” he glanced down at Natsu who was still watching Laxus warily, before adding softly. “They’re looking for a way to get him back to normal now.”

“I see,” Laxus’s expression softened slightly, and after a brief hesitation he crouched so that he was no longer towering over Natsu, struggling to ignore the soft meep that escaped the child at his approach and he offered the Fire mage a tentative smile. “Hi there Natsu, sorry I scared you,” he said softly, his tone gentler than they’d ever heard it before and more than one person rolled their eyes fondly at the scene. Natsu tilted his head as he considered the words, and Gray held his breath as he slowly felt the hands clutching his trousers relax and after a moment Natsu inched out from behind him, studying the other Dragon-slayer with curious eyes.

“You should smile more,” Natsu informed him after a long moment with complete innocence and seriousness as he reached up to pat Laxus’s face, and Gray choked even as he looked anxiously at Laxus to see how he would react, especially as he could hear the laughter spreading around the guild. For a moment all Laxus did was blink, unsure of how to take that comment and knowing that if it had come from the normal Natsu, he would have sent the brat flying, instead after a moment he chuckled softly noting the way that Gray relaxed minutely.

“I’ll try,” he promised with a broader smile, earning a warm grin from the child and he fought the urge to groan slightly…Damn Natsu makes a cute kid, he thought as he slowly straightened trying not to startle Natsu and shooting an amused glance at Gray who was now watching Natsu with a tender expression.

“Come on Natsu let’s go,” Gray encouraged hurriedly as he caught the glance, and Natsu nodded eagerly as he remembered what they were doing and he glanced up at Laxus with a wide smile as he waved up at him.

“Bye Mr Laxus.”

“Bye,” Laxus muttered slightly dazedly as he watched Gray take Natsu’s hand only to be practically dragged out of the guild by the overly excited child, blinking slightly as he shook his head in bemusement before turning to look around, groaning at the amused expressions that met his gaze. Clearly, he wasn’t going to live this down for a while, and he made a mental note to punch Natsu once he got back to his proper size.

****

   Erza and Lucy had tracked Gray and the others down when a couple of hours had passed with no sign of the trio returning to the guild. Levy and Freed still hadn’t made any progress on solving what on earth they had done, and they were slightly worried that something else had happened as they had seen how anxious Gray was at taking the Dragon-slayer out of the safety of the guild. However, their worries melted away the moment their gaze fell on where Gray was gently pushing Natsu back and forth on one of the swings in the main Magnolia park as Happy watched over them from the top of the frame.

“Aren’t they adorable together?” Lucy whispered with a giggle, watching as Natsu shouted loudly for Gray to push harder, the Ice mage complying with a sigh that she could tell was feigned. There were a few curious families who were watching the pair, clearly recognising Gray from his infrequent appearances in Sorcerer's weekly and the incidents involving the town and guild and it was clear they were puzzling over who the child was, and yet Gray was clearly paying them no mind, his attention solely focused on Natsu.

“He’ll make a great dad one day,” Erza replied thoughtfully with a nod, and Lucy choked at her response even though she privately had to agree as she watched Natsu jump off the swing in midair before taking off towards the slide with Gray hot on his heels.

“Gray! Natsu!” She called, and the pair both froze as they turned to look at her, and she could see Gray flushing slightly as he realised that they must have been watching for a while. A heated discussion took place between the two before Natsu reluctantly nodded, trailing after Gray with a scowl as the Ice mage led the way over to them. “We were worried when you were gone so long,” she explained when they reached them, Happy joining them a moment later.

“Sorry,” Gray rubbed sheepishly at the back of his head before glancing down at Natsu and smiling slightly at the sulky expression, before glancing back at them and adding quietly. “Natsu wanted to play longer.” And I can’t say no to him…

“So we see,” Erza said with an amused smile, hearing the unspoken words and knowing that she would have to tease him properly about it later on…when he no longer had the hint of worry in his eyes whenever he looked at Natsu. “But it’s time for tea now Natsu,” she added turning her attention to the Dragon-slayer, noting with amusement that he was beginning to flag now that he had actually stopped and she had to smother a chuckle as he blinked sleepily at her before turning longing eyes back towards the playpark.

“But…”

“You must be hungry after all this playing?” Lucy asked with a warm smile, amused by the fact that Natsu who normally couldn’t be kept away from food was now more interested in playing. Natsu pouted again and shook his head hesitantly, only to flush a moment later when his stomach let out a hungry growl. “See,” she pointed out sharing an amused glance with Gray who was watching their interaction with a small smile playing on his lips, and she knew that he was storing these memories away for after Natsu got back to normal.

“If you’re good I’ll let you have some of my cake after dinner,” Erza interjected as Natsu’s face took on a mulish expression, and he froze his expression immediately brightening even as the other three stared at her in shock…Erza was so protective of her cake that it was practically a once in a blue moon occasion for her to willingly share it with someone else.

“Really?” Natsu asked hopefully staring up at her with wide-eyes, and she smiled at his expression before nodding and replying warmly.

“Really.”

“And you laughed at me for giving in so easily,” Gray muttered to her as Natsu let out a happy whoop before dashing for the entrance, the Ice mage pausing only long enough to smirk at her before chasing after the Dragon-slayer, not trusting him not to get lost in his current state.

****

   Natsu had stubbornly managed to last until the end of tea, just managing to polish off his slice of cake, unaware of the dark glare Erza was giving him at the way he butchered her beloved dessert. However, it was only moments later that his weariness caught up with him and he dozed off at the table, his head nestled in Gray’s lap and his hands twisted firmly into the Ice mage’s shirt as though to stop Gray from escaping as he began to snore softly. With a small laugh, Gray gently petted the messy pink hair for a moment, before gently scooping the sleeping child up in his arms and cradling him carefully against his chest.

“I’m going to put him to bed,” he told the others who were cooing over the sleeping Dragonslayer, rolling his eyes at their reactions even though he was close to doing it too. “I’ll be back in a little while,” he added before heading for the stairs. Makarov had insisted that Natsu stayed in the infirmary until they were able to counteract the spell on him, and Gray had reluctantly agreed although he’d much rather have taken Natsu home…instead, he had stated that he would be staying as well, not that anyone had expected anything different or hand any intention of arguing with him.

“I bet you he falls asleep as well,” Lucy whispered to Erza with a grin as she watched the pair disappear out of sight, and Erza smiled before nodding, knowing that there was no way that Gray would be able to leave Natsu on his own.

“We’ll go and check in a while.”

**

   Sure enough, when they went upstairs half an hour later they found the Ice mage sleeping soundly on the bed, Natsu cuddled up on his chest, drooling slightly as he pressed his face against Gray’s chest. Whenever the Dragon-slayer shifted even slightly, Gray’s brow would furrow for a moment as he rearranged his arms without stirring, his expression only smoothing when Natsu settled once more. Amused Erza quietly tip-toed across to rearrange the covers that the pair had managed to dislodge at some point, whilst Lucy disappeared for a couple of minutes before reappearing with Reedus and his painting tools in tow.

“I want evidence,” she explained when Erza glanced at her curiously, and the older girl had to smother a laugh, knowing that Gray would probably kill them later…and steal a copy of the picture for himself, she added with a fond smile as she stepped back so Reedus could work.

FTFT

“Ow! Ow!” Gray woke suddenly to the sound of pained groans coming from beside him, immediately realising that the small body that had been resting on his chest was no longer there and he sat up with an alarmed cry, only to come up short when his eyes fell on the full-sized Dragon-slayer laying on the bed beside him.

“Natsu?” He asked torn between hope and relief and a strange sense of loss. However, the latter disappeared under a wave of concern as he realised that Natsu was still groaning softly, his hands rubbing over his arms and legs and his voice was anxious as he demanded. “Are you alright?”

“I ache all over,” Natsu muttered finally meeting his gaze, and Gray felt the world right itself as he saw the usual love burning in the olive eyes even as the Dragon-slayer demanded with more than a hint of irritation. “What the hell happened?” Realising that this wasn’t some figament of his imagination, and not caring about how it had happened as Levy and Freed had still been trying to work it out the last he’d heard the Ice mage could resist, throwing himself forward and wrapping his arms tightly around his Dragon-slayer and Natsu’s tone became alarmed as he realised just how tightly Gray was clinging to him. “Huh? Gray? What’s the matter?”

“I’ll tell you in the morning,” Gray mumbled making a note to track down Levy and Freed and find out what had happened, but not lessening his hold on Natsu in the slightest. He had loved the time spent with little-Natsu, and he would cherish those fresh memories, but it didn’t change the fact that it was this Natsu that he wanted more. Biting his lip for a moment he then pulled back, meeting startled olive eyes for a moment before leaning down and pressing a fierce kiss to Natsu’s lips, melting as the familiar warmth engulfed him. This is my Natsu…

“But…” Natsu protested weakly, blinking dazedly up at Gray when the Ice mage pulled back,

before falling silent as he took in the relief swimming in dark eyes, deciding that he could wait for answers after all as it was clear that Gray wasn’t in the mood for supplying them.

“Go back to sleep idiot” Gray muttered as he rolled back onto his back, pulling Natsu with him until the Dragon-slayer was nestled against his chest once more and the Fire mage sighed softly, ignoring the lingering aches and pains and relaxing against his mate. Closing his eyes he hummed contentedly, allowing Gray’s closeness and smell to lull him back towards sleep and just as he was dropping off once more he heard Gray whisper softly in his hear. “Welcome back.” He had no idea what his mate meant, and he was too close to sleep to ask instead settling for sleepily mumbling.

“Tadaima.”


End file.
